The importance of optical switches used to switch optical paths has increased with the development of optical communication technology in recent years. Optical switches include mechanical-type optical switches which have movable parts such as mirrors and electronic-type optical switches which utilize the electro-optical effect, etc. Mechanical-type optical switches are superior to electronic-type optical switches in terms of optical characteristics such as insertion loss and crosstalk, and are superior in terms of essential basic characteristics. However, mechanical-type optical switches are conspicuously inferior to electronic-type optical switches in terms of compactness and mass production characteristics.
With the development of MEMS (micro-electro-mechanical system) technology in recent years, however, mechanical-type optical switches which utilize this technology to improve the degree of integration and mass production characteristics have been proposed.
Conventional mechanical-type optical switches utilizing such MEMS technology use the same principle as that of the switch disclosed in Japanese Patent Application Kokoku No. S56-36401 as the optical path switching principle; in such switches, mirrors capable of a linear motion that allows the mirrors to advance into the optical paths and withdraw from the optical paths are disposed in the form of a two-dimensional matrix. Specifically, such optical switches are constructed from a substrate on which M×N mirrors are disposed, M optical input optical fibers that are disposed along one side of the substrate, and N optical output optical fibers that are disposed along another side of the substrate that is perpendicular to the above-mentioned first side of the substrate. The M×N mirrors are disposed on the substrate in the form of a two-dimensional matrix so that the mirrors are capable of linear motion in the normal direction of the substrate, thus allowing the mirrors to advance and withdraw with respect to the intersection points between the emission light paths of the M optical input optical fibers and the incident light paths of the N optical output optical fibers.
However, in the case of conventional mechanical-type optical switches using the above-mentioned MEMS technology, M×N mirrors disposed in the form of a two-dimensional matrix are required in order to switch light from the M optical input optical fibers to the N optical output optical fibers, so that the number of mirrors is increased. For example, if the light from 1,000 optical input optical fibers is to be switched to 1,000 optical output optical fibers, 1,000,000 mirrors must be disposed on the surface of the substrate in the form of a two-dimensional matrix. Accordingly, although compactness and mass production characteristics have been improved (compared to earlier mechanical-type switches) by the utilization of MEMS technology in the above-mentioned conventional mechanical-type optical switches, this improvement has not always been sufficient.